National Park Refrigerator Magnets
For pole strength, we will employ qm. For example, for a long, skinny bar magnet with its north pole at one end and south pole at the other, the magnetic field near either end falls off inversely with the square of the distance from that pole. Magnets may be used to serve as a fail-safe device for some cable connections. I was to show up at the drive-through window yesterday afternoon at a pharmacy just a mile from my house.
Magnet and Magnetism
Main article: Magnetic field The magnetic flux density also called magnetic B field or just magnetic field, usually denoted B is a vector field. The magnetic B field vector at a given point in space is specified by two properties: Its direction, which is along the Glacier National Park To Great Falls Mt of a compass needle.
Its magnitude also called strengthwhich is proportional to how strongly the compass needle orients along that direction. In SI units, the strength of the magnetic B field is given in teslas. For a bar magnet, the direction of the magnetic moment points from the magnet’s south pole to its north pole, [9] and the magnitude relates to how strong and how far apart these poles are. A magnet both produces its own magnetic field and responds to magnetic fields.
The strength of the magnetic field it produces is at any given point proportional to the magnitude of its magnetic moment. In addition, when the magnet is put into an external magnetic field, produced by a different source, it is subject to a torque tending to orient the magnetic moment parallel to the field.
A magnet may also be subject to a force driving it in one direction or another, according to the positions and orientations of the magnet and source. If the field is uniform in space, the magnet is subject to no net force, although it is subject to a torque. A good National Park Refrigerator Magnets magnet may have a magnetic moment of magnitude 0.
Iron can have a magnetization of around a million amperes per meter. Such a large value explains why iron magnets are so effective at producing magnetic fields. Modelling magnets See also: Two definitions of moment Two different models exist for magnets: magnetic poles and atomic currents. Although for many purposes it is convenient to think of a magnet as having distinct north and south magnetic poles, the concept of poles should not be taken literally: it is merely a way of referring to the two different ends of a magnet.
The magnet does not have distinct north or south particles on opposing sides. If a bar magnet is broken into two pieces, in an attempt to separate the north and south poles, the result will be two bar magnets, each of which has both a north and south pole. However, a version of the magnetic-pole approach is used by professional magneticians to design permanent magnets.
This is a mathematical convenience and does not imply that there are actually monopoles in the magnet. If the magnetic-pole distribution National Park Refrigerator Magnets known, then the pole model gives the magnetic field H.
Outside the magnet, the field B is proportional to H, while inside the magnetization must be added to H. An extension of this method that allows for internal magnetic charges is used in theories of ferromagnetism.
For a uniformly magnetized cylindrical bar magnet, the net effect of the microscopic bound currents is to make the magnet behave as if there is a macroscopic sheet of electric current flowing around the surface, with local flow direction normal to the cylinder axis. Since opposite poles north and south attract, the North Magnetic Pole is actually the south pole of the Earth’s magnetic field.
For example, one method would be to compare it to an electromagnetwhose poles can be identified by the right-hand rule. The magnetic field lines of a magnet are considered by convention to emerge from the magnet’s north pole and reenter at the south pole. Only certain classes of materials can do this. There are…
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Eliminating rolling resistance increases efficiency. For example, the power cords of some laptops are magnetic to prevent accidental damage to the port when tripped over. Placing the item in an external magnetic field will result in the item retaining some of the magnetism on removal.
